This invention relates to a method and apparatus for effecting cooling of elongate material after it has been drawn through a drawing die of drawing apparatus.
In the process of drawing elongate material such as wire, the material upon being drawn through the die or dies has its temperature substantially increased and the drawn materials has to be cooled. The known methods of cooling the material can restrict the speed and production rate of drawing machines. This problem is most severe on multi-die drawing machines where the material is successively drawn through two or more dies and the material can have its temperature increased to a value at which the properties of the material are adversely affected.
It is known to pass the drawn material through a trough or tube containing water but this substantially increases the overall length of the drawing machine which makes threading of the material through the machine difficult. Large quantities of water have to be provided.
It is also known to water cool the inside surface of the capstan of the drawing apparatus which draws the material through the die or dies. A disadvantage of this known cooling system is that heat from the elongate material wound on the capstan has to be conducted through the capstan to the water. The line contact of the drawn material with the capstan, the thickness of the wall of the capstan and the boundary layer of the water form resistances to heat flow and therefore the cooling system is not efficient.
It is also known to spray quantities of water onto the drawn material downstream of the or each die but this method utilizes large quantities of water, with the inherent disadvantage of having to handle large quantities of water. With the trough or tube method and the known spraying method the water which is used to effect cooling is only heated to a temperature below its evaporation point and it is necessary to wipe excess water from the drawn material before it enters the next die.